Crankcase Ventilation System, Function - GF01.20-P-0001MRG
Engine 264.9 in model 213, 238, 257
up to model year 2021
Function requirements, general
- Engine runs
The ME-SFI [ME] control unit (N3/10) detects the engine running via the evaluation of the crankshaft Hall sensor signals (B70). The ME-SFI [ME] control unit directly reads in the signals of the crankshaft Hall sensor.
Crankcase ventilation system, general
The crankcase ventilation system ensures in all engine operating conditions that overpressure and excess gases are removed from the crankcase. These are supplied again to the engine for combustion via the intake air system. To balance out the pressure ratio, a separate line is attached for engine ventilation.
The ME-SFI [ME] control unit evaluates the following signals for the implementation of the crankcase ventilation system:
- Engine load
Pressure and temperature sensor downstream of throttle valve (B28/27)
- Accelerator pedal position
The powertrain control unit (N127) directly reads in the signals of the accelerator pedal sensor (B37) and transmits the accelerator pedal position via the drive CAN (CAN C1) to the ME-SFI [ME] control unit.
- Outside temperature
The front SAM control unit (N10/6) transmits the outside temperature via the interior CAN (CAN B), electronic ignition lock control unit (N73), suspension FlexRay (Flex E), powertrain control unit and drive CAN to the ME-SFI [ME] control unit.
Engine view from left, shown except code M005 (4MATIC)
Crankcase ventilation system
In the partial load range, ventilation takes place starting from the oil separator (1) to the charge-air distributor (2). For this purpose, the partial-load operation crankcase ventilation valve (Y58/2) is located in the partial-load bleed line (3).
The valve is actuated in overrun mode by the ME-SFI [ME] control unit and closes the partial-load bleed line (3) from the oil separator (1) to the charge-air distributor (2).
The inflow of exhaust from the crankcase during the mixture adaptation and disruptive background noise are thus avoided. No actuation from the ME-SFI [ME] control unit takes place if the valve is permanently open.
In full-load operation, ventilation takes place starting from the timing case to the exhaust gas turbocharger.
| Electrical function schematic for crankcase ventilation system | Engine 264.9 in model 213, 238 up to model year 2021 | PE01.20-P-2001-97DBB | |
| Engine 264.9 in model 257 up to model year 2021 | PE01.20-P-2001-97XBC | ||
| Overview of system components for gasoline injection and ignition system with direct injection | GF07.70-P-9998MRG |